Process for weighting of natural and artificial silk fibers



Patented Mar. 21, 1 933 I UNITED STATES PATENT OFFICE.

HARRY EIINTZE, OF PA'IERSON, NEW JERSEY PROCESS FOR WEIGHTING OF NATURAL AND ARTIFICIAL SILK FIBERS No Drawing. Application filed May 18, 1932. Serial No. 611,244.

In processes heretofore made use of for applications of tin-phosphate and their atweighting of natural silk and other fibers, in tendant rinsings, with an average increase in the form of skeins and woven or knitted weight of about 11% for each passage and fabrics, a number of chemical substances aggregate gain of about 40% over the weight 5 were brought into contact with the fibers. of the boiled-off silk.

In practice the use of metallic compounds The purpose of the present invention is to such as ironfor black and navy blue only improve upon the methods now in use and to zinc, alumina, bismuth, tin and lead has been provide a process which will yield very conresorted to; however, a tin-metal solution has siderably more weight with the same number proven best. of passes or one additional pass and which 69 According to the well-known methods now at the same time imparts desirable qualities and heretofore employed, as for instance, the to the natural silk and other synthetic fibers. natural, boiled-off silk is treated first with In the course of extensive experiments, it a solution of tetra-chloride of tinSnCl,. of was found that natural silk and other syn- 15 about 22 Baum strength at a temperature thetic fibers charged with metals such as iron, of 60 F. for some time, and then is rinsed alumina, zinc and tin show a marked aflinity thoroughly with hard water69- hardfor lumbic chloride or di-chloride of leadness-in order to hydrolize the tin and to pre- Pb 1 This particular lead compound recipitate the same on the fiber in the form of sembles in chemical structure the well-known r stannic acidH- SnO This stannic acid pink saltSnCl of commerce and the tetraprecipitate is then fixed by a treatment of the chloride of tinSnGl now universally used silk with di-sodium phosphateHNa .PO for weighting purposes. On account of the of about 7 Baum strength at about 60 C. even and level results obtainable in weightand thereafter rinsed in soft water. The ing with di-chloride of lead and its pure white stannic chloride baths and the phosphate color, it is far superior to other lead combaths are alternately repeated until the depounds, but especially to acetate of lead sired degree of weighting has been obtained, Pb(C I-I O .which has been used for and after each bath or treatment, the silk weighting purposes.

has to undergo a water rinsing or neutraliza- Di-chloride of lead, while known to chemtion as described above. After the last phosical science, has up to the present time never so phate bath and subsequent rinsing, a treatbeen commercially produced to any extent, ment in a solution .of sodium silicate has not been offered for sale by leading manu- -Na SiO -of about 1 Baum strength and facturers, nor is its price quoted, and has at a temperature of 45 C. is applied. The therefore been unobtainable as an article of silk which has been manipulated in this mancommerce and has never been used in the art ner and weighted with complex compounds of weighting natural silk and synthetic fibers, of tin, phosphate and silicate, is then rinsed, known as artificial silk.

soaped and scoured and is ready to be further For purposes of illustration the silk 40 processed by dyeing and finishing.- weighting process is cited: In the present The operations described in the foregoing invention the natural, boiled-off silk is treatparagraph as well as other methods of ed two, three or four times in the old and weighting with various substances, are well well-known manner with stannic metals and known and generally practiced in the indussodium phosphate and thorough rinsings 45 try at the present time. after each bath, producing a gain of from On account of the tendering effect on the 20%-45% over the weight of the boiled-oil tensile strength of the fiber of too heavy and silk. The silk is then worked for one half too many charges of tin-phosphate comhour in a bath containing about 5% of monopounds, and their costs, and the time neceschlor-acetic acid or formic acidbased on sary for the many washings, the weighting the weight of the raw good ;-at F. and

process with tin is generally limited to four subsequently in a bath of an aqueous suspension of di-chloride of lead of 1-5 Baum strength at a temperature of about 160 F. for one hour. After this treatment the goods are copiously rinsed in hard water69 hardnessin order to hydrolize the lead compound and to precipitate same on the fiber in the form of plumbic hydroxide, Pb(OH) This plumbic hydroxide precipitate is then fixed on the fiber by a treatment in an aqueous solution of ammonia carbonateNH H.CO of about 3- 6 Baum strength and of a temperature of 60 F. for about one hour. Subsequently the goods are thoroughly rinsed in soft water and are then ready for silicating and soaping and can be further processed in the usual way by dyeing and finishing.

In order to facilitate the holding in suspension of the di-chloride of lead, it is recommended to add a deci-normal solution of sodium thiosulphate to the bath.

The silicating operation can also be carried out immediately after the tin-phosphate treatment instead of after the lead-weightingr step.

he fibroin of the silk forms a homogenous compound of a very complex nature with the plumbic hydroxide carbonate of ammonia and the stannic acid-phosphate previously deposited in the interior of the fiber by the tin-phosphate treatment.

It is also possible to use instead of carbonate of ammonia for the fixing of the plumbic hydroxide on the fiber, hydroxide of ammonia, mono-sodium phosphate, di-

sodium phosphate or tri-sodium phosphate.

Continuing with the example, if the tinweighted silk is treated in a bath of proper proportions and temperatures according to the directions given above, the tin-weighted natural silk and synthetic fibers are heavily charged with lead-metal compounds and it is possible to obtain from 25% to 65% gain in weight by one single immersion ina di-chloride of lead suspension over and above and in addition to that of the tin-weighted goods.

Added advantages of the process covered by this application are the facts that silk materials so treated show very considerable more tensile strength than those merely tinweighted. Indeed, tin-weighted natural silk as Well as synthetic fibers, tendered in the tinweighted process, so-called tender goods can be restored to their normal strength and have it materially improved by an application of the di-chloride-carbonate of ammonia treatment.

The white produced with this method of weighting is of pure white quality and the goods, therefore, do not have to be bleached for this particular shade nor for other tints requiring a pure white ground, as is the case with goods treated with other forms of lead compounds such as acetate of lead.

Goods intended for printing purposes lend themselves to discharge work under certain conditions.

Furthermore, a decided advantage, compared to only tin-weighted natural silk and synthetic fibers, is the diminished shrinkage of di-chloride of lead-treated goods, representing a gain of from three to six percent in yardage. The draping qualities of silk treated by the methods of this application are far superior, furnishing a fuller and more mellow hand and requiring less finishing materials, without, however, impairing the desirable and peculiar qualities of silk.

The result of the process described above is a composite fiber consisting in a minor part of the fibroin of the silk and in a major part of the compound of tin, lead, phosphate and ammonia carbonate, homogeneously combined and which will give off none of its component elements when treated with acetic acid or other liquids with which the natural silk and synthetic fibers, known as artificial silk, may come in contact during dyeing and finishing operations or when being worn and exposed to perspiration and other secretions of the human body.

It is understood that the term bath employed in the specification and claims designates an aqueous bath. The term fiber in the specification and claims is used in a generic sense and signifies natural or artificial silk fibers in the form of skeins, knitted fabric, woven fabric or any material the body of which is formed of fibers.

I claim:

1. The process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-weighting and fixing agents, treating said fiber in a bath containing di-chloride of lead, and subsequently treating said fiber in a fixing bath.

2. A step in the process of weighting natural and artificial silk fiber which comprises the treatment of the fiber in a bath containing lead chloride.

3. The process of weighting natural and artificial silk fiber which comprises treatingsaid fiber in separate baths with tin-weighting and fixing agents, treating said fiber in a bath containing di-chloride of lead and subsequently treating said fiber in a bath containing ammonium carbonate.

4. The process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-weighting and fixing agents, treating said fiber in a bath containing di-chloride of lead and subsequently treating said fiber in a bath containing ammonium hydroxide.

5. The process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-weight ing and fixing agents, treating said fiber in a bath containing di-chloride of lead and subsequently treating said fiber in a bath containing at least one material selected from a group consisting of mono-sodium phosphate, dil-sodium phosphate and tri-sodlum phos p ate.

6. A step in the process of Weighting natural and artificial silk fiber which comprises the treatment of the fiber in a bath containing di-chloride of lead and a salt inducing the solubility of lead di-chloride in water.

7. A step in the. process of weighting natural and artificial silk fiber which comprises the treatment of the fiber in a bath containing di-chloride of lead and sodium thiosulphate.

8. The process of weighting natural and artificial silk which comprises treating said fiber in separate baths with tin-weighting and fixing agents, treating said fiber in a bath containing sodium silicate, treatin said fiber in a ,bath containing di-chloride 0 lead, and subsequently treating said fiber in a fixing bath.

9. The process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-weighting and fixing agents, treating said fiber in a bath containing di-chloride of lead, treating said fiber in a fixing bath, and finally treating said fiber in a bath of sodium silicate.

10. The process of weighting natural and artificial'silk fiber which comprises treating said fiber in a bath'containing lead chloride and subsequently treating said fiber in a fixing bath.

HARRY HINTZE. 

